On the duality of Phase-based and Phase-less RSSI MUSIC algorithm for Direction of Arrival estimation

In last years the interest in indoor localization techniques is grown very quickly: due to huge increase of interest in domotic technologies and to fast improvement of capabilities for mobile devices, which are becoming always-connected support points for standard users, the capability of making spatial data-contextualization has become an important point of interest. Existing GPS technologies aren’t capable of realizing sufficient accuracy needed for indoor positioning, so it is necessary to find alternative cost-effective methods to resolve localization problem. Excluding odometry-based tracking methods (which present a lot of uncertainty for making an abso- lute positioning), famous signal DoA (Direction Of Arrival) spectral-based localization algorithms like CAPON, ESPRIT, MUSIC[1],[2] provide valid localization accuracy assuming device capability to analyze in real-time physical parameters (amplitude/phase) of received radiocommunication signals to a spatial antenna array. This re- quirement could be achieved using ad-hoc radio equipment, which causes an increase of production costs: maybe, it is far better to develop some kind of new algorithms capable of using standard IEEE wireless protocols infor- mation (like RSS indicator, RSSI) for positioning elaboration. In this article, it will be analytically demonstrated the capability of MUSIC[1] algorithm to elaborate RSSI standard transceiver values (placing some measurement conditions), and there will be shown a comparison between DoA localizations using the classical information set (amplitude/phase) and the RSSI set (obtained simply reading transceiver standard registers).